On my continuing odyssey to analyze real-life circuits as a way to expand my knowledge, I'm studying this Heathkit Curve Tracer:
There are a couple of features about the sweep section power supply I don't fully understand. Here's a snippet of the area of interest:
and here's my (very simplified) re-interpretation of the entire sweep section, to make it easier to digest:
My questions are:
1) Ignoring the high voltage full wave rectifier for now, why does the author tie the bridge rectifier return to the secondary centre tap?
2) What is the purpose of the adjustable low-pass "loop compensation" section highlighted above? How does it work?
Note: I've just realized having laid all this out, that the loop compensation low-pass IS a point of return for the bridge, since it shares a ground point with other parts of the circuit. So, are there two paths back? At any rate, they're both tied back to the C.T., which is confusing to me.
Also, I've noticed from my own analysis, that tying the return to the tap in this way drives more current through each half of the secondary winding on each half cycle. This increases the voltage out of the bridge (possibly as a consequence of a bigger current through the reduced reactance of the half-winding??)